You need to be a company administrator in QuickBooks to add applications.
There are three different user roles in QuickBooks that have these permissions. The “Master Administrator”, the “Company Administrator”, plus two accountants per company.
If you need to import on behalf of the client, then you will need to ask the client for their credentials, or log into their QuickBooks account and manually upgrade your permissions from the 'Manage Users' drop down menu.
From there they can either invite you as an accountant or create you as a new user with 'Company Administrator' privileges.